Merged commit 9079426036c5cf9f9953c1349717aeea8d21fed3

Fixed bug that caused RWLock not to free up entries in txLockElementMap.

The mark flag is used to guard against creating multiple RWLocks for the same resource and has nothing to do with TxLockElement entries.

TxLockElement creation and removal is still safe since it is synchronized on the RWLock.

Conflicts:
	community/kernel/src/main/java/org/neo4j/kernel/impl/transaction/RWLock.java
Merge pull request #2461 from johan-neo/master

Merged commit 9079426036c5cf9f9953c1349717aeea8d21fed3